Spectrometers are of great importance for the analysis of fluids, especially (drinking) water, because they allow measurements of important parameters to be carried out in a contact-free manner and either with or without the addition of additives. This includes, for example, the measurement of the spectral absorption coefficient (SAC), at 254 nm, or the measurement of the total organic carbon (TOC) content.
There is a demand for analytical apparatuses including several and/or replaceable sensor modules, which should be as small as possible. However, the compact design of spectrometers with low-cost components (lenses, gratings and apertures) comes with certain disadvantages. One particular problem is the extensive curvature of the image field, on which the spectrum is imaged. The extensive curvature is a consequence of the limited installation space, which requires lenses having limited focal lengths and thus small lens radii.
It is an object of the invention to provide a compact spectrometer having an improved resolution of the imaged spectrum.